Buyers may be reading too much into simplified school rankings offered on real estate sites, paying premiums of $200,000 or more for homes served by schools that score only slightly better than other schools in the same school district, the San Francisco Chronicle reports.

School district officials in San Mateo County, Calif. say real estate professionals are part of the problem, because they rely on test scores and school ranking sites to help sell homes. They’re holding an event next month to give Realtors a better understanding of what qualities make for a good school.

The Chronicle described a “feeding frenzy” for homes in the city of San Carlos, where the school district’s four elementary schools all score “well above” the state average.

The lowest performing elementary school in the district, Brittan Acres, scored 880 on the state’s 1,000-point Academic Performance Index. While the state considers scores of 800 or above ideal, the other three elementary schools in the district all score above 900.

One buyer withdrew an offer on a home served by Brittan Acres and fired his Realtor when the agent — who serves on the board of a neighboring school district — insisted that the school was fine.

Educators say test scores can often reflect the makeup of a school’s population. Low-income students and those who speak English as a second language can dent overall scores, but high-scoring schools don’t always have the best teachers or programs.